1. Field of the Invention
The present invention relates to a vacuum process apparatus for performing a predetermined vacuum process to a target object such as a semiconductor wafer and a vacuum processing method.
2. Description of the Related Art
Processes in manufacturing a semiconductor include various vacuum processes such as an etching process, a film formation process, an ashing process, and a sputtering process. various vacuum process apparatuses corresponding to these vacuum processes are used. In addition, as these various vacuum process apparatuses, one-by-one type vacuum process apparatuses or batch type vacuum process apparatuses are used. Such a semiconductor manufacturing apparatus is variously devised and improved to cope with a high integration density of a semiconductor and a high throughput. For example, a one-by-one type vacuum process apparatus having the following structure is employed. That is, a plurality of vacuum process chambers are connected to a common convey chamber, and a target object is conveyed into each vacuum process chamber through a common input/output port.
In such an apparatus, a plurality of vacuum process chambers and a cassette chamber are connected to a convey chamber having a convey arm which can be freely reciprocated and rotated, and a wafer cassette in which, e.g., 25 semiconductor wafers are stored is conveyed into a cassette chamber. After the cassette chamber is evacuated, the wafers in the wafer cassette are sequentially conveyed into the vacuum process chambers, and processes are simultaneously performed to the wafers in the vacuum process chambers.
In such an apparatus, unlike in an apparatus in which vacuum process chambers are connected to load lock chambers in a one-to-one correspondence, a convey arm is commonly used in the plurality of vacuum process chambers, thereby achieving a reduction in space. In addition, different processes are performed in the vacuum process chambers, respectively, and one wafer is continuously processed in these process chambers. For this reason, a throughput advantageously increases.
As the convey arm, an arm which is linearly reciprocated is employed. For this reason, the vacuum process chambers and the cassette chamber must be radially arranged with respect to the center of rotation of the convey arm. Although spaces are formed between these chambers, these spaces are dead spaces, and other apparatuses cannot be arranged in the spaces. Therefore, a total space which is actually occupied by the overall apparatus is very large, and the convey arm commonly used in the vacuum process chambers does not provide a great advantage in space. In consideration of arranging the apparatus in an expensive clean room, a reduction in space is further desired.
In addition, since the convey arm is rotatable, a bearing for a rotating shaft must be arranged on the bottom portion in the convey chamber, and particles are easily generated by the bearing when the convey arm is driven. When the degree of micropatterning of devices has increased, countermeasures for removing the particles are required.